The present invention relates to an apparatus for feeding sheet-like articles, in particular printed products such as, for example, newspapers, periodicals, parts thereof and inserts therefor, from a vertical stack thereof.
In a known apparatus of this type (EP-A-0806 391), a sucker arrangement is provided which comprises suction heads which are fitted on a rotor which is driven in rotation. The suction heads, which are connected to a negative-pressure source, are positioned from above on the respectively uppermost printed product of the stack. The printed product are then gripped under the action of the negative pressure acting on the suction opening of a suction head, and are raised off from the stack as the suction head moves further. The sucker arrangement brings the gripped printed product into the active region of a pushing arrangement, which comes to act on an edge of the raised-off printed product. At this point in time, the suction heads are disconnected from the negative-pressure source, as a result of which the gripped printed product is released and pushed away from the stack by the pushing arrangement.
The sucker arrangement thus serves only for raising the printed products off from the stack, while the pushing arrangement performs the task of transporting the printed products away.
This known apparatus requires a comparatively high level of mechanical outlay in order to control the movement of the suction heads. In addition, control means are necessary for periodically connecting the suction heads to the negative-pressure source and disconnecting them therefrom.
Also known are apparatuses which are intended for raising sheet-like articles off from a stack and transporting them away (EP-A-0 585 924 and GB-A-712,337) and have sucker arrangements in which the suction head is guided in a longitudinally displaceable manner in a guide. The suction head is retained in its front, receiving position by means of an elastically deformable restoring element, e.g. a compression spring. If the suction head, with the suction opening connected to the negative-pressure source, is positioned on the uppermost article of the stack, which results in the suction opening being closed, then the suction head automatically moves rearward, counter to the action of the restoring element, into a rear, discharge position. By virtue of this movement of the suction head, the gripped article is raised off from the stack. By virtue of the movement of the sucker arrangement together with the gripped article, the latter is conveyed away from the stack. For the release of the article conveyed away in this manner, the suction head is disconnected from the negative-pressure source.
These solutions thus require a control means for connecting the negative-pressure source to the suction opening of the suction heads and disconnecting it therefrom.
It is an object of the present invention described above, to provide an apparatus of the type with a relatively straightforward design and control which requires less outlay, and allows a stack to be reduced satisfactorily without the products being adversely affected.
The above and other objects and advantages of the present invention are achieved by the provision of an apparatus which comprises a rest for supporting a vertical stack of the articles, a sucker arrangement for lifting the uppermost one of the articles from the stack, and a pushing away mechanism for laterally moving the article which has been lifted from the stack by the sucker arrangement. The sucker arrangement includes at least one suction head which is mounted for movement in a is guide element between a lowered extended position where it engages the uppermost one of the articles in the stack, and a raised retracted position. Also, the suction head has a lower suction opening which is permanently connected to a negative pressure source, and a restoring element is provided for biasing the suction head toward its lowered position.
The specific design of the suction head and the particular design of the pushing away mechanism make it possible for the movement of the suction head to be controlled, without the suction opening being connected to the negative pressure source and disconnected therefrom, solely by the gripped sheet-like articles being pushed away from the suction opening.